package utils;

import java.security.SecureRandom;
import java.util.UUID;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

public class TokenUtil {
	public static String AES = "AES"; // optional value AES/DES/DESede
    public static String CIPHER_ALGORITHM = "AES"; // optional value AES/DES/DESede
    public static String SHA1PRND = "SHA1PRNG"; 

	
	// AES加密
    public static String encryptAccessToken(String content, String password) {
        try {
            SecretKey secretKey = getSecretKey(password);
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, AES);
            Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);// 创建密码器
            byte[] byteContent = content.getBytes("utf-8");
            cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(byteContent);// 加密
//            Base64.getEncoder().encodeToString(result);
            return parseByte2HexStr(result); 
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    // AES解密
    public static String decrypt(String content, String password) {
        try {
            byte[] contentBytes = parseHexStr2Byte(content);
            SecretKey secretKey = getSecretKey(password);
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, AES);
            Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);// 创建密码器
            cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(contentBytes);// 解密
            return new String(result); 
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
    
    public static SecretKey getSecretKey(String password) throws Exception{
    	if(password==null){
    		password = "";
    	}
    	KeyGenerator kgen = KeyGenerator.getInstance(AES);
         SecureRandom random = SecureRandom.getInstance(SHA1PRND);
         random.setSeed(password.getBytes());
         kgen.init(128, random);
//         kgen.init(128, new SecureRandom(password.getBytes()));
         return kgen.generateKey();
    }
    
 // 2进制转16进制
    private static String parseByte2HexStr(byte buf[]) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }
    // 16进制转2进制
    private static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
            return null;
        byte[] result = new byte[hexStr.length() / 2];
        for (int i = 0; i < hexStr.length() / 2; i++) {
            int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
            int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2),
                    16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }
    
    public static void main(String[] args) throws Exception{
    	String content = "PWC"+UUID.randomUUID();
    	String password = "Fujing Zhu";
    	String str= encryptAccessToken(content,password);
    	System.out.println(str);
    	System.out.println("========================");
    	System.out.println(decrypt(str,password));
    }

}
